Rare Progressive Edema From a Secondary Capillary Leak Syndrome in Autoimmune Disease

Secondary capillary leak syndrome (SCLS) is a rare and frequently underrecognized cause of progressive edema, hypoalbuminemia, and noncardiogenic pulmonary edema. We present a case of a 55-year-old man with seronegative rheumatoid arthritis and antisynthetase syndrome on chronic immunosuppression who developed progressive bilateral lower-extremity edema and pulmonary edema in the absence of cardiac, renal, or hepatic disease. Extensive evaluation excluded alternative etiologies. The patient met diagnostic criteria for SCLS and demonstrated clinical improvement with albumin-assisted diuresis. This case highlights an underrecognized autoimmune-mediated phenotype of SCLS and underscores the importance of recognizing progressive edema without shock as a manifestation of SCLS.